In the budget the following March he fired the starting gun and announced a roadmap for the development of small modular reactors (SMRs) would be published in the autumn.

However, it proved to be something of a false start and the industry is getting restless at a lack of action.

Both the roadmap and the results of the first phase of the competition have so far failed to materialise. The only significant update came in August when the Department for Business, Energy and Industrial Strategy (BEIS) accidentally published a list of eligible participants for the competition.

“Evaluation can’t go on forever if we’re going to have an opportunity to realise the potential from small modular reactors”.

Tom Greatrex, chief executive of the Nuclear Industry Association

On the list was American firm NuScale, which is planning to build its first SMR plant in Idaho in 2024. In December it applied for the US equivalent of a generic design assessment (GDA).

“If the UK government does want to get behind the technology, the time to do it is now,” says NuScale managing director for the UK and Europe Tom Mundy.

“When they started this examination of SMRs, they couched it in terms of trying to see SMRs being deployed in the mid-2020s to be part of the solution to the low-carbon objectives.

“When we first started, we were working to that timetable. Every day that we don’t make a decision and move this forward, it does cause the overall programme to slip beyond the mid-20s.”

Also on the list was Rolls Royce. The firm’s senior vice president for nuclear David Orr is similarly keen to see the competition pick up speed. “We believe it’s a once in a generation opportunity for UK companies to design and build the entirety of the plant”.

The promise of SMRs rests on overturning what has generally speaking been a guiding principle of the nuclear industry throughout much of its history – that bigger is better.

Developers hope, among other things, that by building larger numbers of smaller reactors (less than 300MW) in a controlled factory environment, before transporting them on site and combining them to form larger plants, they will be able bring down the cost of nuclear generation.

For the benefits of mass manufacturing to be realised, the reactors will need be produced in the hundreds if not the thousands, and so being the first to market and getting a head start on building up an order book will be a real boon.

“What we need to do is get clarity in the first half of this year because if we’re not careful we’ll start losing first mover advantage in the global market,” warns Orr. “We’re pressing government now for clarity on the SMRs. Our understanding is that [it is coming] within the first quarter of this year.” BEIS has yet to respond to a request for comment.

Tom Greatrex, chief executive of the Nuclear Industry Association, says it’s “understandable” that there have been delays given the events of the 2016 – the Brexit vote, the change in government, and the merging of business and energy departments. Nevertheless, he adds, “evaluation can’t go on forever if we’re going to have an opportunity to realise the potential from small modular reactors”.

He says at least part of that potential rests on being at the forefront of development, adding that the UK is “not the only country in the world” looking at SMRs. “The longer there isn’t progress on the competition, the more difficult that becomes to realise.”

Not everyone is so keen to for the government to channel its efforts into SMRs. Former energy secretary and chairman of community energy group Mongoose Energy, Ed Davey, is among those who are sceptical.

He says his understanding is that the technology will not be able to get “off the ground” until the early 2030s. “So many things are going to have changed by then there has to be really serious question mark over whether these things will have any value at all to us.”

Although he has “no problem” with the government exploring the potential of SMRs through a competition, he says it should really be focusing its research efforts on storage technologies.

“In terms of what our priorities should be you need to deliver a lot of new low-carbon kit in the 2020s and I see no evidence that small modular reactors can do that. SMRs have a danger of being a distraction.” To bet the UK’s energy future on SMRs without some “hard evidence” on costs would be “risky and highly irresponsible”.

The extent to which SMRs can play a useful role in the UK’s energy mix remains unclear. It will depend on the untested hypothesis that mass manufacturing can bring down the cost, and so supporting their development will be a gamble. However, if the government believes that this is a horse worth backing, then it will need to hurry up and get out of the gates.